02.09.02.05.TwoIsBetterThanOne

using System;
using System.Text;

class TwoIsBetterThanOne
{
    static int FindPalindromesNumber(ulong fromNumber, ulong toNumber)
    {
        int counter = -1;
        StringBuilder sb = new StringBuilder();
        for (ulong i = fromNumber; i <= toNumber; i++)
        {
            if ((i % 10 == 3 || i % 10 == 5) && (i % 100 == 3 || i % 100 == 5 || i % 100 == 33 || i % 100 == 55 || i % 100 == 53 || i % 100 == 35))
            {
                sb.Append(i);
                sb.Append(' ');
            }
        }
        string numbersToCheck = sb.ToString();

        string[] checkCollection = numbersToCheck.Split();

        foreach (string txtNumb in checkCollection)
        {
            int length = (txtNumb.Length / 2);
            bool sign = true;

            for (int i = 0; i < length; i++)
            {
                if ((txtNumb[i] != txtNumb[txtNumb.Length - 1 - i] && (txtNumb[i] != '3' || txtNumb[i] != '5') && (txtNumb[txtNumb.Length - 1 - i] != '3' || txtNumb[txtNumb.Length - 1 - i] != '5')) || (txtNumb[i] == '0' || txtNumb[txtNumb.Length - 1 - i] == '0'))
                {
                    sign = false;
                    break;
                }
            }

            if (txtNumb.Length < 2)
            {
                if (sign == true)
                {
                    counter++;
                    //Console.WriteLine(txtNumb);
                }
            }
            if (txtNumb.Length >= 2)
            {
                if (sign == true && ((txtNumb[(txtNumb.Length / 2)]) == '3' || (txtNumb[(txtNumb.Length / 2)]) == '5'))
                {
                    counter++;
                    //Console.WriteLine(txtNumb);
                }
            }
        }

        return counter;
    }

    static void Main()
    {
        string inpNumbes = Console.ReadLine(); //"1 99";
        string[] splitFirst = inpNumbes.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);

        ulong fromNumber = ulong.Parse(splitFirst[0]);
        ulong toNumber = ulong.Parse(splitFirst[1]);

        int counter = FindPalindromesNumber(fromNumber, toNumber);
        Console.WriteLine(counter);

        string inputList = Console.ReadLine(); //"-2,-1,-4,-3";
        string[] splitInput = inputList.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
        int[] sortedNumbers = new int[splitInput.Length];
        for (int i = 0; i < sortedNumbers.Length; i++)
        {
            sortedNumbers[i] = int.Parse(splitInput[i]);
        }
        Array.Sort(sortedNumbers);

        string percentage =  Console.ReadLine(); // "50";
        decimal percentNumber = decimal.Parse(percentage);

        decimal checkNumber = (decimal)(sortedNumbers.Length * percentNumber / 100.0m) - 1;
        decimal rounder = Math.Round(checkNumber, 0);
        int member = (int)rounder;
        Console.WriteLine(sortedNumbers[member]);
    }
}